What is hiberfil.sys, and can you remove it?
Short answer: hiberfil.sys is where Windows saves memory to hibernate and for Fast Startup. It is often several GB. You cannot delete it like a normal file, but turning hibernation off removes it.
By hand, with Windows' own tools
- Open Terminal as administrator.
- Run
powercfg /hibernate off. The file disappears and the space comes back. - To turn it back on later:
powercfg /hibernate on.
With Sparewise
- Shows how big the hibernation file is on your PC and what turning it off changes.
- Points to the Windows command; it never deletes system files itself.
Questions
Is it safe to turn off hibernation?
Yes, if you do not use Hibernate. Fast Startup also stops, so a cold start may take a few seconds longer.
Why is hiberfil.sys so large?
It is sized to a share of your memory, so PCs with more RAM have a bigger file.
Get Sparewise, free
Get it from the Microsoft Store or download the installer
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